The then five-month-old tot was baptized at the private chapel in Windsor in April 2004, and she was the last royal baby to wear the original royal christening gown.
The late Queen Elizabeth II commissioned her personal wardrobe advisor, Angela Kelly, to create a replica of the 1841 royal christening gown, which had become too delicate.
The replica was first worn by Lady Louise’s younger brother, James, Viscount Severn, at his baptism in 2008.
Lady Louise, who was born one month prematurely at Frimley Park Hospital in November 2003, is currently studying English at the University of St Andrews – where her older cousin, Prince William, met his future wife, Kate Middleton.
Prince Edward and Sophie chose five godparents for their daughter – the Earl’s cousins, Lady Sarah Chatto, Lord Ivor Mountbatten and Lady Alexandra Etherington, as well as the couple’s friends, Rupert Elliott and Francesca Schwarzenbach.
While Edward and Sophie carry out full-time royal duties, it is expected that Lady Louise and James will forge their own career paths in future.